Component member of constructions



Dec. 29, 1970 HIDEO YANAl 3,550,339

COMPONENT MEMBER OF CONSTRUCTIONS Filed June 26, 1968 2 Sheets-Sheet 1 lHllJllllJUlWHl1W(HHUlHllWHHHHHlI 1 WW HIDED YANM, 'INVENTOR ATTORNEYS HlDEO YANAI COMPONENT MEMBER OF CONSTRUCTIONS I Dec. 29, 1970" Filed June 26, 1968 2 Sheets- Sheet 2 FIG. 7

H\DEO YANM.

INVENTOR BY I ATTORNEYS United States Patent 3,550,339 COMPONENT MEMBER OF CONSTRUCTIONS Hideo Yanai, 414, 3-chome, Chuo, Nakajima, Oita-shi, Japan Filed June 26, 1968, Ser. No. 740,295

Claims priority, application Japan, July 3, 1967,

42/ 42,370 Int. Cl. E04!) 1/14; E04c 3/34; G05d 11/34 U.S. Cl. 52-250 4 Claims ABSTRACT OF THE DISCLOSURE Mechanically strong, light-weight component members of generally horizontal load bearing constructions which are subjected to repeated application of bending load, said component members each comprising an outer pipe made with a material having a highly increased resistance to the applied tensile load, an inner member such as steel pipe or V-shape steel member inserted in said outer pipe, and a mass of concrete having a sufiicient resistance to the applied compressive load, said mass of concrete being filled tightly in the space defined by said inner member and said outer pipe, so that the applied tensile load is adapted to be borne by said inner member and said outer pipe and that the applied compressive load is adapted to be borne by said mass of concrete.

BACKGROUND OF THE INVENTION (a) Field of the invention The present invention is concerned with an improvement in the basic component member structure, such as cross bars and girders, of constructions which are subjected to repeated application of bending load. As is well known, the stress which is created in a cross bar or a girder of a construction along a longitudinal sectional plane thereof varies in nature and direction with the positions in which the sections of the cross sectional plane of said girder are located. More specifically, the stress which is created in the section of a girder above the neutral plane thereof consists of a compressive stress, whereas the stress which is created in the section of the girder which is located below the neutral plane thereof consists of a tensile stress. Thus, when a bending load is applied to a girder or a cross bar which is supported at two spaced points, there are created, in said girder, groups of stresses; the direction of the stress of one of the group is the opposite of that of another group, depending on the section of the girder which is subjected to the bending load. Therefore, unless the group of stress which is created in the upper section of the girder relative to the longitudinal neutral plane of the girder is balanced with the groups of stresses which are created in opposite direction in the lower section of the girder relative to said neutral plane, it is impossible to obtain a girder which is both economical and of a highly increased mechanical strength.

(b) Description of the prior art Cross bars and girders which have been widely used in the past as the constituent members of constructions, such as overhead (elevated) highways and bridges, have employed ferro-concrete members or shape steel members. While ferro-concrete cross bars and girders had an advantage, on the one hand, that they were available at a relatively cheap price, they had the overwhelming drawbacks, on the other hand, in that the constructing operations which were carried out by the use of ferro-concrete cross bars or girders required much time and a great deal of labor and that such a constructing operation lacked speediness. Such a constructing operation of the 3,550,339 Patented Dec. 29, 1970 prior art comprised the following steps. That is to say, the operation started with the fabrication of the wooden frames into which wet concrete was to be poured. Then, iron bars or rods were arranged securely inside each frame. Thereafter, concrete was poured into the frames so as to have the iron bars or rods embedded therein. After the foregoing steps, the resulting filled-up frames were left to stand for a substantial length of time till the wet concrete dried up. Thus, the preparation of ferro-concrete cross bars or girders of the prior art consumed a lot of time and labor.

Aside from the use of the aforesaid ferro-concrete component members, there has been equally popularly utilized shape steel members as the component members of constructions. However, in order to expect as great a resistance to the applied bending load from the shape steel members as that from the ferro-concrete constituent members, it has been mandatory to use shape steel members which had a highly increased sectional modulus. This resulted in the undesirable hike in the cost of constructions.

SUMMARY OF THE INVENTION It is, therefore, an object of the present invention to eliminate the aforesaid disadvantages and drawbacks of the conventional constituent members of constructions and to provide component members which are much lighter in weight than those members of the prior art and which are nevertheless of a highly increased sufficient mechanical strength.

Another and more specific object of the present invention is to provide component members of generally horizontal load bearing constructions which are light in weight and money-saving and which are of a mechanical strength sufficient to resist the applied bending load, by the arrangement of each component member in such a way that it comprises an outer member consisting of a pipe made with a material having a sufiicient resisting property to the applied bending load, an inner member selected from the group consisting of pipe and shape article made with a material having a comparably resisting property to the applied bending load, and a mass of concrete packed tightly in the space defined by the inner member and the outer member, said arrangement being such that the applied tensile load is adapted to be borne by both the outer and the inner members and that the applied compressive load is adapted to be borne by said mass of concrete which is packed in said space.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view, with parts broken away, of one embodiment of the component member of construction of the present invention;

FIG. 2 is a diagram showing the distribution of the load applied to a component member;

'FIG. 3 is a diagram of the bending moment which is created in the component member in FIG. 2 when the load is applied in the manner as shown in FIG. 2;

FIG. 4 is a longitudinal sectional view of an embodiment of the component member of the present invention which is arranged so as to cope with the bending moment which is created in such a way as is shown in FIG. 3;

FIG. 5 is a longitudinal sectional view of a part of the component member which embodies the present invention and which is located on a supporting member;

FIG. 6 is a longitudinal sectional view of a component member representing another embodiment of the present invention;

FIG. 7 is a longitudinal sectional view of a component member embodying the present invention and being applied as a girder of a bridge; and

FIG. 8 is a cross sectional view of a plurality of those component members shown in FIG. 7 and arranged in side-by-side relations relative to each other and being taken along the line VIIIVIII in FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will hereunder be described in further detail in connection with a couple of examples thereof by referring to the accompanying drawings which are given simply by way of example. It is to be understood, however, that the present invention is not restricted only thereto, and that various modifications of the present invention may be made by those skilled in the art without departing from the spirit of the present invention.

In the drawings, like parts are indicated by like reference numerals for the simplicity of explanation. As will be clearly understood from FIG. 1 which represents one example of the present invention, an inner steel pipe 2 is inserted in an outer steel pipe 1 which is of a inner diameter greater than the external diameter of said inner steel pipe 2. The portion of the internal wall of the outer steel pipe 1 wherein it is brought into contact with the external wall of the inner steel pipe 2 which is inserted through the outer steel pipe 1 is welded to said portion of the inner steel pipe 2 so as to fix these two pipes firmly along the said portions of the walls thereof. The space which is defined by the external wall of the welded inner steel pipe 2 and by the internal wall of the welded outer steel pipe 1 is filled densely and tightly with a mass of wet concrete 4 which is allowed to solidify in said space.

The inner steel pipe 2 is disposed in the outer steel pipe 1 in such a way that said inner steel pipe 2 is located on the side which is subjected to the tensile load which will be applied to the completed component member and that the mass of concrete 4 is located on the side which is subjected to the compressive load which will be applied to the completed component member. More specifically, the mass of concrete 4 and the steel members 1 and 2 are arranged in such a way that the mass of concrete 4 which is packed in the space defined by the external wall of the inner steel pipe 2 and the internal wall of the outer steel pipe 1 will bear the compressive load which will be applied to the completed component member and that the inner steel pipe 2 which is inserted in the outer steel pipe 1 will bear the tensile load which will be applied to the completed component member. The mass of concrete 4 is of a sufficient force to resist the compressive load which is applied thereto, but it is poor in its resistance to the tensile load which is applied thereto. Shape steel, on the other hand, exhibits a greater mechanical strength against the applied tensile load than against the compressive load which is applied thereto. Thus, according to the present invention, the features of these different individual materials which constitute the component member are utilized most effectively and efiiciently so as to fully display their own inherent strongpoints and to also compensate for their weak points, so that, as a result, it is possible to provide ideal component members for those constructions which are subjected to repeated application of bending force which is exerted thereto externally thereof.

Description will hereunder be directed to the relationship between the bending load applied, the bending moment thereby created and the component members of the present invention.

In case an equally distributed load is applied to a component member X in a manner as illustrated in FIG. 2, there is obtained a diagram of moment which consists of such patterns of bending moment for each section of the component member. as are shown in FIG. 3. More specifically, the sectional bending diagram can be prepared in the form of a parabola which contains points of contrafiexure D and D located slightly within the supporting members A and B, as shown in FIG. 3.

Therefore, in case a component member of a construction is to be used under a condition as shown in FIG. 2, this component member will, according to the present invention, have the following structure. Specifically, in order to cope with the blending moment which is created in the component member in a manner as illustrated in the bending moment diagram of FIG. 3, the inner steel pipe 2 which is contained in the outer steel pipe 1 and the mass of concrete 4 which is packed in the space formed between the inner steel pipe 2 and the outer steel pipe 1 are disposed, respectively, in a manner as shown in FIG. 4, that is to say, in such an arrangement that, in the section of the complete component member X where said section i subjected to a positive bending moment, the inner steel pipe 2 is disposed closer to the bottom wall of the outer steel pipe 1 and the mass of concrete 4 is disposed in the space so that the mas of concrete 4 is located on top of said inner steel pipe 2. On the other hand, in the sections of the complete component member X where said sections are subjected to a negative bending moment, the arrangement of the mass of concrete 4 and the inner steel pipe 2 are the inverse of that of the section which is subjected to a positive bending moment, that is to say, the inner steel pipe 2 is disposed closer to the top wall of the outer steel pipe 1 and the mass of concrete 4 is disposed in the space so that the mass of concrete 4 is located substantially beneath the inner steel pipe 2. In other words, the relative positions of the inner steel pipe 2 and the mass of concrete 4 are inverted at the points of contraflexure D and D, so that the complete component members will each have a sufficiently and highly increased resistance to the bending forces applied thereto.

Furthermore, as will be noted in FIG. 5, a mass of concrete 4 is packed also in the inner steel pipe 2 in the section thereof where it is located on the supporting member to prevent the component member from collapsing in case an overwhelming compressive load is exerted thereupon.

There has been described an example of the component member structure wherein an inner steel pipe 2 is fixed to an outer steel pipe 1 inside the latter. As an alternative, however, the inner steel pipe 2 may be substituted by a V-shape steel member 2' having a V-shape cross section, in such a way that this V-shape steel member 2 is inserted through the outer steel pipe 1 and that a mass of concrete 4 is filled in the space which is defined by the section of the inner wall of the outer pipe 1 between the edges of the diverging walls of the V-shape steel member 2' which are in contact with and fixed to said inner wall of the outer steel pipe 2 and also by the two diverging walls of the V-shape steel member 2 and also that the apex of the V-shape steel member 2 is welded to the inner wall of the outer steel pipe 1.

It is to be noted also that the material with which the outer pipe 1 and the inner pipe or shaped member 2 are formed is not limited to only steel, but instead, these members may be made with a reinforced plastic (F.R.P.)

As has been described, it will be understood clearly by those skilled in the art that by the use of these component members of the present invention, there can be built, for example, a bridge with an extremely great easiness and with a greatly reduced manufacturing cost. More specifically, in order to build a bridge, there are laid the opposite end portions of a plurality of component members X in side-by-side relationship on a steel plate 7 which has been fixed, in the form that said plate 7 spans the supports 5 and 5 and that the steel plate 7 extends beyond the supports 5 and 5, in advance to the concrete supports 5 and 5 by means of leg members generally indicated at 6 which are embedded vertically in the upper faces of said concrete supports 5 and 5. In such an instance, the inner pipe 2 or the inner shape member is disposed within the outer pipe 1 on the side which is subjected to a tensile load, whereas the mass of concrete 4 is disposed on the side which is subjected to a compressive load. In other words, the inner pipe 2 or the shaped member is disposed closer to the bottom wall of the outer pipe 1, whereas the mass of concrete 4 is disposed on top of said inner pipe 2 or the shaped member. The component members X each having the aforesaid structure and being arranged in side-by-side relationship are fixed, by welding, to the steel plate 7. Then, the upper faces of these component members X are fixed, by welding, to the under face of another steel plate 8. Thereafter, a layer of pavement 9 is formed on top of said steel plate 8, and as a result, there is formed a bridge, as will be noted in FIG. 7.

What is claimed is:

1 Component members of generally horizontal load bearing constructions, each comprising an outer pipe having a circular cross sectional configuration and having sufiicient mechanical strength to resist a bending load applied thereto, an inner pipe having a circular cross sectional configuration but having an outer diameter smaller than the inner diameter of said outer pipe, said inner 20 pipe being inserted in said outer pipe and fixed to the inner wall of said outer pipe to divide the interior of said outer pipe into two spaces extending longitudinally thereof, and concrete filled in that space in said outer pipe surrounding said inner pipe inserted in said outer pipe, whereby as said bending load is applied to said outer pipe a part of the compressive stress created in said outer pipe is borne by said concrete.

2. Component members according to claim 1, wherein the relative positions of said inner pipe inserted in said outer pipe and said mass of concrete filled in said space are inverted at the points of contrafiexure of bending moment created in said component member due to the bending load applied thereto externally.

3. Component members according to claim 1, wherein a mass of concrete is filled tightly also in the space in said inner pipe in the section thereof which is located on a supporting member supporting said component members.

4. A bridge structure comprising supports on which the end portions of said component members described in claim 3 are laid and fixed thereto.

References Cited UNITED STATES PATENTS 304,790 9/1884 Butz 52-731 596,217 12/ 1897 Rapp 52-725 908,127 12/ 1908 Passmore 138-116 2,574,241 11/1951 Bobst 52-731 3,331,177 7/1967 Godfrey 52-727 3,088,561 7/1963 Ruzicka 52-727 FOREIGN PATENTS 14,823 8/1895 Great Britain 138-111 816,464 10/1951 Germany 138-115 823,864 12/1951 Germany 138-115 FRANK L. ABBOTT, Primary Examiner J. L. RIDGILL, JR., Assistant Examiner US. 01. X.R, 5 -124; 13s 111, 174 

